Coronavirus: First COVID-19 vaccine to be tested on people appears to be safe

The first SARS-CoV-2 coronavirus vaccine to be tested on people appears to be safe and is able to trigger an immune response against the disease, the vaccine's US manufacturer, Moderna, has announced.

The findings are based on results from the first eight people to be administered two doses of the vaccine. Moderna's human trials began in March as pharmaceutical companies across the globe raced to develop a vaccine in response to the pandemic, which has killed more than 315,000 people.

The healthy volunteers, aged 18 to 55, produced antibodies that were subsequently tested in infected cells. It was found that the antibodies had successfully stopped the virus from replicating. As reported by the New York Times, the levels of the "neutralising" antibodies matched, or exceeded, the levels found in patients who had recovered from a case of community transmission. 

Moderna said that additional testing in mice found the vaccine could prevent the virus from replicating in their lungs. The animals also had levels of neutralising antibodies comparable to those found in the people who had received the vaccine.

However, the findings do not prove the vaccine is successful at preventing the virus. Whether or not it works effectively in the real world can only be determined by much larger and longer studies.

In April, the World Health Organization (WHO) revealed its three leading candidates in the race to develop a vaccine to the novel coronavirus, which has infected almost 5 million people worldwide. The top candidates were the Beijing Institute of Biotechnology in partnership with Hong Kong's CanSino Biological Inc and US biotechnology companies Inovio Pharmaceuticals and Moderna, the latter in collaboration with the National Institute of Allergies and Infectious Diseases (NIAID). 

The NIAID, Moderna's collaborator, is led by top US physician and immunologist Dr Anthony Fauci, a prominent voice throughout the pandemic. The institute has been leading the clinical trials and is involved in research on other experimental coronavirus vaccines. 

Several other candidates have also begun human trials, including Pfizer and its German partner, BioNTech, and the University of Oxford in collaboration with AstraZeneca.

Phase 1 of Moderna's testing process is still ongoing, with two more age groups - 55 to 70 and 71 and over - now being enrolled to test the vaccine. Phase 2, which will recruit 600 participants, is due to begin soon, while a third phase, involving thousands, is expected to begin in July.

Moderna's chief medical officer Dr Tal Zaks told local media that if the trials are successful, a vaccine could be ready for public use by the end of this year or early 2021 - although the number of available doses remains unclear. Experts have agreed that in order to meet global demand, multiple vaccines must be developed - as the widespread need for doses would far outweigh one manufacturer's production capacity.

As reported by the New York Times, it's likely the vaccine will be administered via two shots, four weeks apart - meaning that however many doses are produced, only half that number can actually be vaccinated.

Low, medium and high doses of the vaccine have been tested in the human trials, the only adverse reaction being redness and soreness in one patient's arm where the medication was administered. However, three patients who received the highest dose developed temporary fevers, headaches and muscle pains, Dr Zaks confirmed, although the symptoms went away after a day. 

However, the highest dose is being eliminated from future studies, the New York Times reports, as the lower doses appeared to be sufficient and would allow Moderna to produce a larger quantity of the vaccine. 

Researchers at Moderna and the NIAID discovered that part of COVID-19's genetic sequence, shared by Chinese scientists online earlier this year, codes for a spike-like protein on the surface of the virus that attaches to human cells, helping the virus to invade them. 

Yet the company's relatively new technology, which involves a segment of genetic material from the virus called messenger RNA, or mRNA, has yet to produce any approved vaccine available on the market. 

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